Willyamit

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Willyamit
Willyamite.jpg
Black, metallic willyamite aggregate from the type locality Broken Hill , New South Wales, Australia
General and classification
other names

Antimony nickel cobalt luster

chemical formula
  • CoSbS
  • (Co, Ni) SbS
Mineral class
(and possibly department)
Sulfides and sulfosalts
System no. to Strunz
and to Dana
2.EB.25 ( 8th edition : II / C.06b)
02.12.03.04
Crystallographic Data
Crystal system orthorhombic, pseudocubic
Crystal class ; symbol orthorhombic-pyramidal; mm 2
Space group Pca 2 1 (No. 29)Template: room group / 29
Lattice parameters a  = 5.86  Å ; b  = 5.86 Å; c  = 5.86 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 5 to 5.5
Density (g / cm 3 ) measured: 6.76 (3)
Cleavage completely after {001}
Break ; Tenacity uneven; brittle
colour steel gray
Line color grey black
transparency opaque
shine Metallic luster

Willyamite is a seldom occurring mineral from the mineral class of "sulfides and sulfosalts" with the idealized chemical composition CoSbS and thus, chemically speaking, a cobalt - antimony - sulfide .

Willyamite crystallizes in the orthorhombic crystal system and occasionally develops pseudocubic crystals a few millimeters in size with zonal growth patterns. The mineral is in any form opaque ( opaque ) and displays on the surfaces of the steel-gray crystals have a metallic luster .

With Ullmannite (NiSbS), willyamite forms a complete mixed crystal row , which is why part of the cobalt in willyamite is usually replaced ( substituted ) by nickel . In various sources, the formula for willyamite is therefore also given as (Co, Ni) SbS.

Etymology and history

The mineral was discovered by the then sub-administrator George Smith in the Consols Mine near the Broken Hill mining settlement in the Australian state of New South Wales . It was first described in 1893 by the Australian mineralogist Edward Fisher Pittman (1849-1932), who had the chemical analysis carried out by the chemist from the Mining Authority, JCH Mingaye.

Based on the analysis results, Pittman regarded the mineral as cobalt- nickel- sulfantimonide (essentially Co 0.5 Ni 0.5 SbS), but assumed that it was mixed crystal formation based on the same proportions of cobalt and nickel and confirmed further discoveries could that cobalt and nickel could represent each other in the compound. Ullmannite, discovered in 1843, would be the best mixed crystal partner. As a name for the newly discovered mineral, Pittman suggests Willyamite, based on the official name Willyama from its type locality Broken Hill after the Aboriginal word for "hill with a broken contour".

In later publications, Willyamite is not recognized as an independent mineral type, but rather viewed as a cobalt-containing variety of Ullmannite, including in 1962 by NL Markham and LJ Lawrence and in 1969 by Peter Bayliss . In order to clarify the chemical composition for willyamite, Louis J. Cabri, DC Harris, JM Stewart and JF Rowland carried out new investigations in 1970 on two museum samples which, according to the labels, were from Broken Hill and Consols Lode (= Consols Mine), Broken Hill, NSW originated. It turned out that the type mineral samples were complex crystal formations with zones with very different Co: Ni ratios. Cabri et al. therefore spoke out in favor of redefining the name Willyamit as the cobalt-rich members with Co> Ni of the mixed series CoSbS – NiSbS and the mixed formula (Co, Ni) SbS. The newly defined end link formula CoSbS for Willyamit has been recognized by the International Mineralogical Association (IMA).

The type material of the mineral is in the National Museum of Natural History in Washington, DC (USA) under the catalog no. R849A kept.

classification

Already in the outdated 8th edition of the mineral systematics according to Strunz , the willyamite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with [the substance ratio] M: S <1: 1", where it belonged to the now discredited kallilite and Ullmannit the "Ullmannit series" with the system no. II / C.06b within the "cobaltin-ullmannite group" (II / C.06).

In the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , the mineral was given the system and mineral number. II / D.18-30 . In the "Lapis Classification" This also corresponds to the department "sulfides with [molar ratio] Metal: S, Se, Te <1: 1" where Willyamit with Cobaltit , Gersdorffit , Hollingworthit , Irarsit , Jolliffeit , Kalungait , Milotait , Platarsite , tolovkite and ullmannite form the "cobaltite group" (II / D.18) (as of 2018).

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and was updated by the IMA until 2009, classifies the willyamite in the newly defined section of “metal sulfides with a molar ratio of M: S ≤ 1: 2”. This is further subdivided according to the exact molar ratio and the predominant metals in the compound, so that the mineral can be found in the sub-section "M: S = 1: 2, with Fe, Co, Ni, PGE etc." according to its composition where it together with Changchengit, Cobaltit, Gersdorffit-P213 , Gersdorffit-Pa3 , Gersdorffit-Pca21 , Hollingworthit, Irarsit, Jolliffeit, Kalungait, Krutovit , Maslovit, Mayingit , Michenerit, Milotait, Padmait, Platarsit, Testibiopalladit, Tolovkit and Ullmannit the " Gersdorffitgruppe "with the system no. 2.EB.25 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns willyamite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here, however, it is in the " cobaltite group (cubic or pseudocubic crystals) " with the system no. 02.12.03 within the subsection "Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 2".

Chemism

According to the idealized (theoretical) composition of willyamite (CoSbS), the mineral consists of a mass fraction (% by weight) of 27.70% cobalt (Co), 57.23% antimony (Sb) and 15.07% sulfur (S) .

In the samples from the type locality (TL), the levels fluctuated in the range described by Cabri et al. analyzed zones I to IV for cobalt between 23.2 and 9.9% by weight and for nickel between 17.1 and 3.8% by weight. The highest cobalt concentration of 25.2% by weight (Ni 1.4% by weight) could be measured at an edge of the crystal from the Smithsonian Institution (sample R849, TL Consols Lode, Broken Hill). The mass fractions of antimony and sulfur remained relatively stable in the measuring zones between 54.7 and 56.6% by weight Sb and 14.6 and 15.1% by weight S. In addition, small amounts of iron (Fe) between 0 were added , 1 and 0.4% by weight and arsenic (As) between 0.4 and 1.6% by weight.

Crystal structure

Willyamite crystallizes orthorhombically in the space group Pca 2 1 (space group no. 29) with the three apparently identical lattice parameters a  = 5.86  Å ; b  = 5.86 Å and c  = 5.86 Å as well as four formula units per unit cell . The three axes are within a tolerance of 0.001 Å, which is the reason for the pseudocubic crystal formation of willyamite. Template: room group / 29

Modifications and varieties

The compound is trimorphic and, in addition to the orthorhombically crystallizing willyamite, also occurs in the orthorhombically crystallizing modifications costibit and paracostibit , which, however, have a different space group and different lattice parameters .

Education and Locations

Willyamit forms in calcite - siderite - veins , where he next calcite and siderite, you still with Dyskrasit and Costibit socialized occurs.

As a rare mineral formation, Willyamite could only be detected in a few places worldwide, with almost 30 sites being documented so far (as of 2020). In Australia , the mineral was found in addition to its type locality in the Consols Mine and other surrounding pits at Broken Hill in New South Wales in the pits at Mount Isa and in Cloncurry Shire in Queensland.

Within Northern Europe , the mineral occurred in the Ettedal Pit (also Espeland ) in the Norwegian municipality of Vegårshei ; in the pit ENases in Ljusdal , copper and cobalt deposit Håkansboda in Lindenberg and in some sites in Tunaberg 14 km south-southwest of Nykoping in Sweden and in the copper-zinc deposit Outokumpu North Karelia and the Satulinmäki - prospecting with gold-bearing quartz veins at Somero in Finland.

In Central Europe , Willyamit has so far been found at Oberhüttensee near Forstau in the Salzburger Land with outcrops of a layered uranium (sulfide) mineralization and in a former quarry on Klipitztörlstrasse between Stelzing (district of Hüttenberg ) and Lölling in Carinthia in Austria; in a quarry near Vlastějovice (German Hammerstadt ) antimony ores in hydrothermal veins near Zruč Sázavou nad the Czech district Kutna Hora and in Ozdín , Hnúšťa and Mútne ( Mutnik ) in Banská Bystrica District and Betliar , Nižná Slaná and Rakovnica in Okres Kosice of Slovakia.

The only known site for willyamite in southern Europe is the former mine Argentiera della Nurra with syngeneic - submarine-exhalative Ni-Co-As-Sb-Fe-Pb mineralization near Porto Torres on the Italian island of Sardinia .

Other locations include China, Canada, Kazakhstan, Russia and Tanzania.

See also

literature

  • Edward F. Pittman: Note on the occurrence of a new mineral at Broken Hil . In: Journal and Proceedings of the Royal Society of New South Wales . tape 27 , 1893, pp. 366–375 (English, rruff.info [PDF; 561 kB ; accessed on June 20, 2020]).
  • Louis J. Cabri, DC Harris, JM Stewart, JF Rowland: Willyamite redefined . In: Proceedings - Australasian Institute of Mining and Metallurgy . tape 233 , 1970, pp. 95–100 (English, researchgate.net [PDF; 2.8 MB ; accessed on June 20, 2020]).
  • Michael Fleischer : New mineral names . In: American Mineralogist . tape 56 , 1971, p. 358–362 (English, rruff.info [PDF; 343 kB ; accessed on June 20, 2020]).
  • René TM Dobbe: Ullmannite, cobaltian ullmannite and willyamite from Tunaberg, Bergslagen, central Sweden . In: The Canadian Mineralogist . tape 29 , 1991, pp. 199–205 (English, rruff.info [PDF; 1.3 MB ; accessed on June 20, 2020]).

Web links

Commons : Willyamite  - collection of images, videos and audio files

Individual evidence

  1. a b c d Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  105 (English).
  2. a b Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2020. (PDF; 2.44 MB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2020, accessed June 20, 2020 .
  3. a b c Stefan Weiss: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  4. a b c d e f g Willyamite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 52  kB ; accessed on June 20, 2020]).
  5. ^ A b David Barthelmy: Willyamite Mineral Data. In: webmineral.com. Retrieved June 20, 2020 (English).
  6. ^ TG Vallance: Pittman, Edward Fisher (1849-1932). In: adb.anu.edu.au. Australian Dictionary of Biography , accessed June 20, 2020 .
  7. ^ A b Edward F. Pittman: Note on the occurrence of a new mineral at Broken Hil . In: Journal and Proceedings of the Royal Society of New South Wales . tape 27 , 1893, pp. 366–375 (English, rruff.info [PDF; 561 kB ; accessed on June 20, 2020]).
  8. ^ A b c d Louis J. Cabri, DC Harris, JM Stewart, JF Rowland: Willyamite redefined . In: Proceedings - Australasian Institute of Mining and Metallurgy . tape 233 , 1970, pp. 95–100 (English, researchgate.net [PDF; 2.8 MB ; accessed on June 20, 2020]).
  9. Ernest H. Nickel , Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF; 1.82 MB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed June 20, 2020 .
  10. ^ Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  108-109 (English).
  11. Localities for Willyamite. In: mindat.org. Hudson Institute of Mineralogy, accessed June 20, 2020 .
  12. Tunaberg. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on June 20, 2020 .
  13. Klipitztörlstrasse. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on June 20, 2020 .
  14. Argentiera della Nurra. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on June 20, 2020 .
  15. List of locations for willyamite from the Mineralienatlas and Mindat , accessed on June 20, 2020.